Carburetor throttle cracker



April 13, 1954 Filed June 1, 1951 O. J. EICKMANN CARBURETOR THROTTLECRACKER 4 Sheets-Sheet l INVENTOR. OLIN J. EICKMANN ATTORNEY Ap 13, 1954o. J. EICKMANN 2,675,216

CARBURETOR THROTTLE CRACKER Filed June 1, 1951 4 Sheets-Sheet 2JNVENTOR. OLIN *J. EICKMANN ATTORNEY April 1954 o. J. EICKMANN 2,675,216

CARBURETOR THROTTLE'CRACKER Filed June 1, 1951 4 Sheets-Sheet 5 FIGS 33INVENTOR. OLIN J. EICKMANN k ww ATTORNEY April 1954 o. J. EICKMANN2,675,216

CARBURETOR THROTTLE CRACKER 4 Sheets-SheetA Filed June 1 1951 INVENTOR.OLIN J. EICKMANN ATTORNEY Patented Apr. I3, 1954 UN ITED STATES PATENTOFFICE.

CARBURETOR THROTTLE CRACKER;

011ml. EickmanniNormandy, Mo., assignor to. Carter CarburetorCorporation, St. Louis, Mo.,. a corporation of Delaware Application June1, 1951, SerialNm 229,356.

This invention relates to internal. combustion engine carburetors of theanterior throttletype and consists in novel throttle control meanstherefor, particularly, to facilitate. starting.

It has been foundthat in a downdraft carburetor of the anterior throttletype, fumesv may collectbeneath the throttle valve, particularly, inwarm weather, and hinder restartingv of the engine. Another problem insome. carburetors. of this type is-that the-throttle valve, normallymanually controlled, must not be opened during starting at very lowtemperatures.v

Accordingly, the'main object of the present invention is to provide "anovel throttle control mechanism which insures slight opening orcracking of the 'throttle valve, after the engine is stopped, forventing vapors.

Another object is to provide a thermostatic control for such athrottle-cracking device so that the throttle may be returned tosubstantially fully closed position atlow 'temperatures to facilitatestarting.

Another object is to provide stop means for positively preventingopening of the throttle valve, atlow temperatures, until the enginestarts to run.

These objects and other more detailed objects hereafterappearing-areattained by the mechanism illustrated in the accompanyingdrawings in which Fig. 1 is a side view-showinga portion of themanifolding of an internal combustion engine with an anterior throttlecarburetor mounted thereon.

Fig. 2 is an enlarged top viewof the carburetor.

Fig. 3 is a vertical, transverse section taken on line 3-3 of Fig. 2.

Fig. 4. is a detail elevation-taken on line 4-4 of Fig. 3. Fig. 5 is aside view of the carburetor show- 'ing the throttle valve and relatedparts in their fcold cranking-positions, portions being broken away andsectioned for clearer illustration.

weather starting;

Fig. 9 is'a view of thesameparts as in Figs. "7

and 8; but showing" the throttle control parts 8 Claims. (Cl; 261-.39)

during normal operationof. the associated engine.

Fig. 1 shows portions ofv anintake manifold l0 and exhaust manifold .IIwhich join in a hot spot structure 12 upon whichismounted thecarburetor, generally indicated at 13. A stove It, mounted on theexhaust manifold, .isconnected by a tube I5 to a thermostat housing Hi,to. be described. An accelerator rod. I]. extends from the driver'scompartment and is. connected through a coiled spring l8andznut stops,l9. toa lever so which is loosely mounted about throttle shaft 2! (Fig.5).

Rigid with throttle shaftll and immediately adjacent lever isasecondlever 22 having a radial extension23 with. an. inturned finger 24.This finger is constantly urged against a radial finger 25, projectingfromthe periphery of loose lever, 20 by a torsion spring. 26 having itsends hooked about fingers 24 and 25, as shown. An idle adjusting screw21 is received by. threaded ears 28 on lever 20 and engages a. stop29 onthe carburetor body tolimit the closed or normal idling position of thethrottle valve.

A butterfly throttle valve 3| is mounted on shaft 2! in the air entranceportion. 32. of the carburetor mixture conduit. Adjacent the mixtureconduit, is a constant level chamber 33 within which fuel is maintainedat a substantially constant level by a float 34 and needle valvemechanism (not shown). Main fuel, nozzle 35 (Fig. 3) projectsupwardlyand inwardly from the lower part of the constant levelchamber anddischarges into the throatof primary Venturi tube 36.

Leading upwardly from the mainfuel nozzle is an air bleedductfll whichcommunicates with the mixture conduit adjacent the edge of the throttlevalve by means of the vertically spaced, differently sized ports 38"andis-connected by passages 39 and 40 (Fig. 2) to a tube 41 projecting intothe mixture conduit.

"a needle valve screw 50. A branch passage 5| connects passage flto thetop of 'a constant level chamber 33. A thermostatic, bi-metal coil 52mounted within housing It has its outer extremity hooked about andarranged to actuate an an gular finger 53 rigid with drum valve 45. Thethermostat is heated by warm air from stove l3 and tube [5 to shift thedrum valve to increase the effective size of the communication throughslot 46 between passages 44 and 4'! connecting the mixture conduit andthe space at the top of the fuel bowl. At low temperatures, thisefiective communication is reduced to a minimum and a port 54 in thedrum valve admits air from housing [6 into the mixture conduit. Much ofthe above, with the exception of the throttle control parts, is coveredin a copending application, Serial No. 164,544, filed May 26, 1950, inmy name.

Formed on the outside of the mixture conduit is .a vertical cylinder 58communicating by means of a passage 51 with the interior of the.

mixture conduit. A piston 58 works in the upper part of this cylinderand normally projects thereabove. The piston is urged upwardly by acompound, coiled, bi-metal spring 59, shown in detail in Fig. 6, whichis of the character to extend along its principal axis, upon increase oftemperature, to urge piston 58 upwardly.

Figure 8 shows the condition of the parts when the engine is stopped athigh temperature with accelerator rod I! fully relaxed to permit maximumclockwise rotation of throttle loose lever 20 by means of return spring66. Due to the elevation of piston 58, which underlies and interfereswith inward finger 24 on rigid lever 23, the throttle valve, if openwhen the engine stops, can return only to the adjusted position shown indotted lines, torsion spring 25 flexing to permit this relative movementof the two throttle levers. Ordinarily, the engine is stopped with thethrottle closed; however, when suction is not present in cylinder 56,the thermostat spring 59 tends to expand when the engine is hot, whichwill raise piston 58 to open the throttle 3i from its idle position toits venting position against the resistance of spring 26.

Figure 5 shows piston stop element 58 in its lowered position, as undercold temperatures, permitting tight lever 23 to rotate clockwisesuificiently so that the throttle valve may be fully closed under theinfluence of its return spring, when the accelerator is released,permitting adjusting screw 21 to engage stop 29. Figs. 5 and 3illustrate the two extreme posi-- tions of the throttle adjusting device58 and 59. The tension in actuating spring 59 depends on enginetemperature. Accordingly, the force it exerts, tending to open, ortending to resist, throttle closing, as the case may be, will dependupon temperature. It is wholly possible, therefore, for the throttle toassume other positions between these extreme positions as the enginecools or is stopped before reaching full operating temperature.

In the fully closed position of the throttle, a detent 6|, which worksin a cylinder 62 and is urged constantly upwardly by a coiled spring 53,enters a recess 64 in the periphery of loose lever 25. As shown inFigure 7, engagement of detent 6| with the inclined shoulder 65 ofrecess 64 impedes counter-clockwise motion of loose lever 25 and,consequently, opening movement of the throttle valve. If acceleratorlink i! is actuated in the throttle opening direction, spring I8 isfirst compressed, as shown, while the throttle remains closed, or opensonly slightly. However, upon extreme actuation of the accelerator linkin the throttle opening direction, sufficient force will be built up inspring l8 to cause inclined shoulder 66 to ride over detent 6|,permitting opening of the throttle valve, as in case it is necessary tounload excess fuel which may be discharged into the manifold duringstarting. This latching of the throttle in closed position is desirableat low temperatures in order to facilitate starting. Cylinder 62 isconnected by a passage 61 to the interior of the mixture conduit so thatwhen the engine starts to run under its own power, sufiici-en't suctionwill be created within the mixture conduit to draw detent Bl downwardly,thus releasing the throttle valve for complete opening movement underthe influence of accelerator linkage I1. I

The latching of the throttle valve in a partially open position, as inFig. 8, is desirable in order that any fumes rising from the manifold orfrom the main'fuel nozzle will not be trapped beneath the throttle valveso as to impede restarting. Granking suction applied to piston 58 willtend to lower the same against the thermostatic spring and, at moderateand high temperatures, the piston stop element will be loweredsufficiently during cranking to permit closing of the throttle valve, byreturn spring lit, to the desirable position for starting. When theengine is operating normally under its own power, both piston 58 anddetent 6| will be drawn downwardly to their non-stopping positions topermit free actuation of the throttle valve under the influence of theaccelerator linkage and return spring, as usual.

The thermostatic spring may be calibrated to provide for the properstarting position of the throttle valve under various temperatures.Broadly, another type of device responsive to operation of the engine,such as a motor responsive to oil pressure or a magnetic deviceresponsive to generator output, may be .substituted for the suctionmotor 56, 58 for counteracting the warm thermostat after the engine isin operation. Moreover, the exact type of thermostat as shown is notessential and other types may be substituted. Some features of theinvention are applicable to other types of carburetor mixture conduitvalves, other than the anterior throttle, as shown. The exclusive use ofall modifications as come within the scope of the appended claims iscontemplated.

I claim:

1. In combination with an internal combustion engine, an air supplyconduit a throttle valve in said conduit for controlling the flow of airto said engine, a fuel nozzle discharging below said valve, means formoving said valve towards closed position, a part movable with saidvalve, a device cooperating with said part for adjusting the position ofsaid valve when the engine is at rest to provide for venting vapors fromsaid conduit, said device including a mechanism connected to said-deviceand responsive to operation of the engine to shift said device to aninactive position with respect to said part.

2. In combination with an internal combustion when the engine is at restto provide for venting vapors from said conduit, a second conduit forconducting a flow of fluid upon operation of the engine, including ameans responsive to fluid fiow in said second conduit to shift theadjusting position of said device with respect to said part.

3. In combination with an internal combustion engine induction conduit,a flow controlling throttle valve therein, a fuel discharge nozzle insaid conduit below said valve, manual means to open said valve andspring means for moving said valve toward closed position when saidmanual means is released, a device cooperating with said part foradjusting the position of said valve when the engine is at rest toprovide for venting vapors from said conduit, and means connected tosaid device and said conduit and responsive to suction in said conduitto shift said device to permit further closing of said valve.

4. In combination with an internal combustion engine, an air supplyconduit a valve in said conduit for controlling the flow of air to saidengine, a fuel nozzle discharging into said conduit below said valve,manual means to open said valve and means for moving said valve towardsclosed position whenever said manual means is released, a part movablewith said valve, a device cooperating with said part for adjusting theposition of said valve when the engine is at rest to provide for ventingvapors from said conduit, said device including a mechanism connected tosaid device and responsive to operation of the engine to shift saiddevice to an inactive position with respect to said part, said deviceincorporating a thermostat adapted to vary the adjusted position of saidpart and said throttle when the engine is not in operation.

5. In combination with an internal combustion engine, an air supplyconduit, a valve in said conduit for restricting the flow of air to theengine, a fuel nozzle discharging below said valve, means to move saidvalve towards closed position when the engine is at rest, a part movablewith said valve, a throttle adjusting element movably mounted adjacentsaid part and cooperable therewith to hold said valve at least partlyopened when in active position, a second conduit for accommodating afluid flow incident to actuation of the engine, a fluid motoroperatively con nected to said conduit and said adjusting element, forshifting said element upon operation of the engine, to permit furtherclosing of said valve, and a thermostatic spring constantly urging saidadjusting element towards its active position, said position being suchas to hold said valve partly open at high temperature for venting vaporsrising from said nozzle into said air conduit and to permit substantialclosing of said valve at low temperatures.

6. In a carburetor for internal combustion engines, a mixture conduit, amanually operable throttle valve in said conduit near the air entrancethereof, a fuel reservoir, a main fuel nozzle extending upwardly fromsaid reservoir and discharging into said conduit posterior to saidvalve, a lever movable with said valve, a throttle adjusting elementcooperable with said lever, a throttle return spring, a thermostatnormally urging said element to an active position, at high temperatureto position said valve at least partly opened for venting vapors issuingfrom said nozzle, and a suction motor operatively connected to saidconduit and said adjusting element for shifting said element from itsactive position upon actuation of said motor, said thermostat shiftingsaid element to a position when the temperature is low, to permitclosing movement of said valve by said return spring.

7. In a carburetor for internal combustion engines, a mixture conduit, athrottle valve in said conduit near the air entrance thereof, a fuelreservoir, a main fuel nozzle extending upwardly from the reservoir anddischarging into said conduit posterior to said valve, a lever movablewith said valve, a throttle adjusting element cooperable with saidlever, a throttle return spring, a thermostat normally urging saidelement to an active position, at high temperature, to force said valveat least partly opened for venting vapors issuing from said nozzle, anda suction motor operatively connected to said conduit and said adjustingelement for shifting said element from its active position uponactuation of said motor, said thermostat responding to a drop intemperature to reduce its resistance to movement of said adjustingelement by said suction motor so that cranking suction in said conduitwill shift said adjusting element and permit substantial closing of saidvalve by said throttle return spring to facilitate starting.

8. In a carburetor, a mixture conduit, an anterior throttle therein, amain fuel nozzle discharging into said conduit posterior to said valve,a manual control yieldingly connected to said throttle for opening thesame, a throttle return spring, a thermostatically controlled stop forlimiting closing of said valve at high temperatures when said manualcontrol is released, a second stop for limiting opening of said valve,

and suction motor means responsive to suction in said conduit forshifting both of said stops upon operation of the engine, to permitcontrol of said valve by said manual control and said return spring.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,393,290 Chandler Jan. 22, 1946 2,403,720 Hunt July 9, 19462,540,607 Boyce Feb. 6, 1951

